1. Field of the Invention
The present invention relates to a fabricating method of a MEMS device, and more particularly, to a fabricating method of a MEMS microphone.
2. Description of the Prior Art
Microphones are electromechanical transducers that convert an incident pressure into a corresponding electrical output. There are many well-established transduction principles but the condenser microphone stands out due to its high sensitivity, low power consumption, high noise immunity and flat frequency response.
MEMS microphones work on a principle of variable capacitance and voltage by the movement of an electrically charged diaphragm relative to a backplate electrode in response to sound pressure.
Generally, the position which the diaphragm and the logic device is located is called the front side of the wafer. The side which does not have the logic device is called the backside of the wafer. Recent MEMS microphones form the backplate electrode after the formation of the diaphragm, the logic device and the metal interconnections. However, in the conventional fabricating method, the step of forming the trenches from the backside of the wafer requires a longer fabricating time.